The present invention relates to the field of non-metallic cut and abrasion resistant composite yarns and to more economically combine yarns for use in the manufacture of composite yarns, and more particularly to the application of air intermingling technology to the manufacture of such combined yarns.
The present invention relates to composite yarns useful in the manufacture of various types of protective garments such as cut and puncture resistant gloves, aprons, and glove liners. It is well known in the art to manufacture such composite yarns by combining yarns constructed of non-metallic, inherently cut-resistant materials using wrapping techniques. For example, these yarns may use a core construction comprising one or more strands that may be laid in parallel relationship or, alternatively, may include a first core strand that is overwrapped with one or more additional core strands. A representative sample of such yarns includes that disclosed in U.S. Pat. Nos. 5,177,948; 5,628,172; 5,845,476; and 5,119,512. The composite yarns described above can be knit on standard glove-making machines with the choice of machine being dependent, in part, on the size of the yarn.
Wrapping techniques are expensive because they are relatively slow and often require that separate wrapping steps be made on separate machines with intermediate wind up steps. Further, those techniques require an increased amount of yarn per unit length of finished product depending on the number of turns per inch used in the wrap. Generally, the greater the number of turns per inch, the greater the expense associated with making the composite yarn. When the yarn being wrapped is high performance fiber, this cost may be high.
Knitted gloves constructed using a relatively high percentage of high performance fibers do not exhibit a soft hand and tend to be stiff. This characteristic is believed to result from the inherent stiffness of the high performance fibers. It follows that the tactile response and feedback for the wearer is reduced, which is highly undesirable, particularly since the gloves typically are used in meat-cutting operations around sharp blades.
It would be desirable to maximize these qualities in a cut-resistant and non-cut-resistant yarn strands using a different, less expensive and time consuming technique to create a single combined strand, while optimizing the properties of resultant yarns and products manufactured therefrom.
The present invention provides novel cut-resistant combined yarns by intermittently air interlacing one or more strands of a cut resistant material with one or more strands of a non-cut resistant material or fiberglass. The resulting combined yarn is useful alone or with other yarns in manufacturing garments, such as gloves that have surprising softness, hand and tactile response.
The invention further relates to a method of making a non-metallic cut resistant combined yarn including the steps of feeding a plurality of yarn strands into a yarn air texturizing device strands to form attachment points intermittently along the lengths of the strands, wherein the plurality of strands includes:
(i) at least one non-metallic strand comprised of an inherently cut resistant material;
(ii) at least one non-metallic strand comprised of a non-cut resistant material or fiberglass; and
(iii) at least one of the strands being a multifilament strand.
The invention permits one of ordinary skill to take advantage of the ability of a non-cut resistant fiber strand and/or a fiberglass strand to provide support for a high performance, cut-resistant fiber without the need for expensive wrapping techniques. The air interlacing approach permits several strands of both cut resistant and non-cut resistant and/or fiberglass materials to be combined in a number of different combinations depending on the materials available and the desired characteristics of the finished product. This combination can be achieved using fewer manufacturing steps than would be required with the techniques applied thus far to the preparation composite, cut resistant yarns.
The two or more strands are air interlaced with each other to form a single combined strand or yarn having attachment points intermittently along the length of the single combined strand. The composite yarns of the invention can be used alone in the manufacture of items such as cut resistant garments, or can be combined with another parallel yarn during product manufacture. Alternatively, the combined yarns may be used as a core yarn in composite yarns, with a first cover strand wrapped about the combined strands in a first direction. A second cover strand may be provided wrapped about the first cover strand in a second direction opposite that of the first cover strand.
Processes involving treatment of yarns with air jets are well-known in the prior art. Some of these treatments are used to create textured yarns. The term xe2x80x9ctexturingxe2x80x9d refers generally to a process of crimping, imparting random loops, or otherwise modifying continuous filament yarn to increase its cover, resilieance, warmth, insulation, and/or moisture absorption. Further, texturing may provide a different surface texture to achieve decorative effects. Generally, this method involves leading yarn through a turbulent region of an air-jet at a rate faster than it is drawn off on the exit side of the jet, e.g., overfeeding. In one approach, the yarn structure is opened by the air-jet, loops are formed therein, and the structure is closed again on exiting the jet. Some loops may be locked inside the yarn and others may be locked on the surface of the yarn depending on a variety of process conditions and the structure of the air-jet texturizing equipment used. A typical air-jet texturizing devices and processes is disclosed in U.S. Pat. No. 3,972,174.
Another type of air jet treatment has been used to compact multifilament yarns to improve their processibility. Flat multifilament yarns are subjected to a number of stresses during weaving operations. These stresses can destroy interfilament cohesion and can cause filament breakages. These breakages can lead to costly broken ends. Increasing interfilament cohesion has been addressed in the past by the use of adhesives such as sizes. However, air compaction has enabled textiles processors to avoid the cost and additional processing difficulties associated with the use of sizes. The use of air compaction for high strength and non-high strength yarns is disclosed in U.S. Pat. Nos. 5,579,628 and 5,518,814. The end product of these processes typically exhibits some amount of twist.
Other prior art, such as U.S. Pat. Nos. 3,824,776; 5,434,003 and 5,763,076, and earlier patents referenced therein, describe subjecting one or more moving multifilament yarns with minimal overfeed to a transverse air jet to form spaced, entangled sections or nodes that are separated by sections of substantially unentangled filaments. This intermittent entanglement imparts coherence to the yarn, avoiding the need for twisting of the yarns. Yarns possessing these characteristics are sometimes referred to in the prior art as xe2x80x9centangledxe2x80x9d yarns.
While intermittent air entanglement of multifilament yarns has been to impart yarn coherence, the application of this concept for interlacing dissimilar yarns including a cut resistant yarn component has not been recognized, nor has the resultant advantages and properties of combined yarns resulting from the application of this technology.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiments when considered in conjunction with the drawings. It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention.